Ignition Power Stage: Description and Operation

PURPOSE
The power stage functions as an electronic switch controlling the current in the ignition coils on command from the ECU. This function is comparable to the operation of the points in a mechanical ignition system, in that it opens and closes the coil primary ground connection.

Component Location:

LOCATION
The two power modules are located on the upper radiator support.

OPERATION AND SIGNAL
When the ECU has computed ignition timing (based on input signals), the value is converted into a control signal for the power stage. When the signal goes high (+ 5V), the power stage permits the ignition coil to charge. When the signal falls (to 0V), the power stage interrupts the current in the ignition coil primary windings, inducing a high-tension pulse in the secondary windings.


The power stage incorporates a circuit which monitors and controls the current used to charge the ignition coil. This keeps the current supplied to the coil at a constant level, assuring a full charge at all times.